From owner-freebsd-hackers Mon Aug 12 13:34:03 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id NAA16846 for hackers-outgoing; Mon, 12 Aug 1996 13:34:03 -0700 (PDT) Received: from phaeton.artisoft.com (phaeton.Artisoft.COM [198.17.250.211]) by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id NAA16818 for ; Mon, 12 Aug 1996 13:33:55 -0700 (PDT) Received: (from terry@localhost) by phaeton.artisoft.com (8.6.11/8.6.9) id NAA25973; Mon, 12 Aug 1996 13:24:13 -0700 From: Terry Lambert Message-Id: <199608122024.NAA25973@phaeton.artisoft.com> Subject: Re: FreeBSD vs. NT Stability To: lada@ws2301.gud.siemens.co.at (Hr.Ladavac) Date: Mon, 12 Aug 1996 13:24:12 -0700 (MST) Cc: terry@lambert.org, narvi@haldjas.folklore.ee, igor@jabber.paco.odessa.ua, freebsd-hackers@FreeBSD.ORG In-Reply-To: <199608121901.AA164676506@ws2301.gud.siemens.co.at> from "Hr.Ladavac" at Aug 12, 96 09:01:46 pm X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > > Other than some experimental code that I did which never made it > > into the UnixWare 2.x release, I don't know of *any* user/kernel > > hybrid threads implementations, sorry. > > Isn't SunOS 5 threads over LWP's such a hybrid (at least according to > a rather ancient documentation which I had in hand.) No, it is not. The ability to associate multiple user contexts with a smaller number of shedulable kernel entities is a means of assigning number of quantum to a threaded process. The implementation does *NOT* cooperatively schedule user contexts to run on top of kernel entities based on kernl conversion of a blocking operation to an async operation + a context switch. I've already had this discussion with Bryan O'Sullivan of Sun Microsystems and other at USL... The confusion probably results from the University of Washington's user threads implementation (Paper: SPARC Register Windows and User Space Threading) that was the basis of Sun's LWP (Light Weight Process) user space thread implementation in SunOS 4.x. This is not to be confused with kernel schedulable entities in Solaris (also called LWP's or Light Weight Processes). The name space clash was probably done for the same reasons that Sun calls Solaris SunOS: marketing (Q: Can I buy SunOS? A: Yes, we would love to sell you "SunOS". Q: Does SunOS support LWP's? A: Yes, the "SunOS" you will be buying supports "LWP"'s just fine...). Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.